Project summary/abstract: Chronic pain afflicts up to one in five adults and is the most common cause of long-term disability in the world. Opioids, which are commonly prescribed for non-cancer pain, are associated with a high incidence of serious effects and abuse. Moreover, current in vivo and in vitro models used to study nociception and test potential treatments are inadequate. Human-based, pathology-relevant models of nociception are urgently needed to facilitate preclinical development of new non-opioid pain therapeutics. Therefore, we propose to develop an innovative 3D model of acute and chronic nociception using hiPSC sensory neurons and satellite glial cell surrogates (an hiPSC-based DRG tissue mimic) on multi-well MEAs. In the UG3 phase, we will develop a tissue chip for modeling acute and chronic nociception based on 3D hiPSC-based dorsal root ganglion (DRG) tissue mimics and a high-content, moderate-throughput microelectrode array (MEA) platform. DRG tissue mimics will be comprised of hiPSC counterparts to constituent intraganglionic DRG cell types embedded in a collagen matrix. We will then demonstrate stable spontaneous and noxious stimulus-evoked behavior in response to thermal, chemical, and electrical stimulation challenges. Furthermore, we aim to demonstrate the clear functional and phenotypic advantages of utilizing a 3D mixed-cell DRG tissue mimic versus purely neuronal 2D or 3D models. More specifically, we aim to demonstrate sensitivity to translational control via ligand receptor interactions between neuronal and non-neuronal cell types, thereby demonstrating pathological relevance to a the ?holy trinity? of pain (nociceptive, inflammatory and neuropathic) and our model?s capacity for testing fundamental hypotheses related to contributions of non-neuronal support cells in chronic pain development and maintenance. In the UH3 phase, we will demonstrate the powerful quantitative efficiency and preclinical efficacy of our microphysiological system by detecting known ligand-based modulators of translational control and voltage- gated ion channel antagonists in a sensitized model of chronic nociception. These two classes of drugs are widely recognized as candidate compounds for reversing nociceptive plasticity and/or serving as peripheral analgesics. Moreover, we will quantitatively define pharmacological hits based on widely accepted assay scoring methodologies. Lastly, we will leverage the high-throughput nature or our tissue chip model to screen FDA- approved, bioactive compounds, demonstrating the sensitivity and throughput of our high content assay, and potentially identifying efficacy of candidate therapeutics obscured by less sophisticated methods of phenotypic screening.